In general, machine-to-machine (M2M) communications refer to connectivity between a large number of machine-type devices that communicate with each other or with a connected service without need for human intervention. In M2M communications, also commonly referred to as machine-type communications (MTC), machines (devices) can directly communicate with one another or can make use of a common network, such as the Internet.
The M2M market is quickly growing and some forecasts estimate that billions of machine-type devices will be deployed in the coming decade. Applications for these machine-type devices include smart metering, smart grid, surveillance, security, vehicle-to-vehicle communications, intelligent transportation system (ITS), e-health, industrial Internet, cloud computing, and the like.
Some of the challenges for MTC include:                1) Massive Connections. The number of connected MTC devices is growing. It is expected the number of deployed MTC devices will increase by at least an order of magnitude within a decade. Many of these devices will rely upon a connection to a wireless network which may overwhelm current Long Term Evolution (LTE) based wireless networks;        2) High coverage for supporting remote sensors. It has been estimated that the link budget of a network supporting a large number of MTC devices will need to be 15 dB to 20 dB above GSM 900/UMTS 900/LTE 800;        3) Cost of hardware. Due to large number of meters and sensors, the cost per device needs to be low to enable successful commercial deployment. It is expected that the per device cost will need to be in the range of one to two dollars to achieve wide scale commercial use;        4) Power Consumption. Many meters and sensors are expected to be powered by batteries and some may have only intermittent access to other power sources. Due to the cost constraints and power limitations, it is expected that MTC devices may require a standby time in the target of several years for a single battery; and        5) Asynchronous transmission mode. Currently deployed wireless networks typically rely upon device synchronizing with a base station to synchronize transmissions to defined time windows. This can be burdensome to implement in a low cost device with limited power supply. A reduction in signaling overhead caused by the need for synchronous transmissions would also be desirable.        
Therefore, there is a need for a system and a method for supporting MTC with large numbers of machine-type devices while meeting the challenges described above.